Centrifugally controlled device



May 15, 1951 c. H. MINER CENTRIFUGALLY coNTRoLLED DEVICE 'Filed March17, 1949 IN V Ely TOR. HMI/2er Zar/es A 7' T ORA/EY atented May l5.,1.951

UNITED STATES A'reNT FFICE 12 Claims. l

This invention relates to centrifugally controlled power transmissiondevices.

In certain types of power transmission systems the .torque of the primemover, such as an internal combustion engine or an electric motor, isrelatively low at low speeds and increases as the prime mover increasesits speed. Thus, gasoline engines such as used in automobiles,motorcycles, and the like, have a torque-speed curve wherein the torqueincreases somewhat in direct proportion to angular velocity. Similarly,certain types of electric motors have low starting torque and in orderto bring a driven load up to a desired speed it is necessary to providea larger motor than necessary for rated load conditions in order thatthe rated load speed may be achieved. In automobiles, `for example, itiscustomary to provide selective speed transmissions so that suitableacceleration of the vehicle may be achieved, or to provide sufcientpower to operate the Vehicle under certain driving conditions, such asstarting the automobile into motion, the transmission permitting theengine to operate at higher speeds where it develops greater torque. theautomobile gains momentum the ratio between the engine and wheels isreduced by steps with the transmission. One form of the invention hereindisclosed relates to transmission devices for this purpose, althoughcertain of the principles employed have wider application as willhereinafter appear.

One of the objects or" the invention is to pro- ,Vide a belttransmission device which automatically changes the ratio between driverand driven elements in response to change in speed, the change occurringin infinitesimal increments.

Another object is to provide a belt transmission device of the foregoingtype wherein the driven element is automatically disconnected, orVdeclutched, from the driver below a predetermined speed of the latter.Y

Another object is to provide a system of pulleys wherein the driverpulley increases in pitch diameter in response to increase in speed,resulting in a higher ratio between driver and driven pulleys at higherspeeds.

Another object is to provide Va variable speed transmission in which theratio between driver and driven elements may be selected for a givenspeed of the driver element. A

Another object is to provide a V-belt sheave,

which in one position, disconnects a V-belt therefrom, and in' otherpositions provides a pulley of variable pitch diameter, depending uponpulley (Cl. i4-230.17)

Another object is to control the size of the ipitch diameter of a V-beltsheave by thecentrifugal force .exerted by a train of contactingspherical members.

A further object is to centrifugally actuate a plurality of ,sphericalmembers in such manner that the centrifugal forces acting on certain ofthem becomes ineiective to produce a force on one end of the train, atcertain speeds of operation.

Further objects, advantages, and salient features will become moreapparent from a consideraton of the description to follow, the appendedclaims, and the yaccompanying drawing, in which:

Figure l is a cross section of a variable ratio drive pulley 4taken online I--I, Figure 2;

Figure 2 is a section taken on line 2-2, Figure 1;

Figure 3 is a cross section through an alternative application of theinvention, a centrifugal actuator being employed to control a clutch;

Figure 4 is a cross section through a centrifugal actuator utilized forgeneral application;

Figure 5 is a section taken on line 5 5, Figure 1;

Figure 6 is a diagrammatic view of a belt transmission system driving atone ratio;

Figure '7 is a similar View in another ratio; and

Figure 8 is a fragmentary sectional View of a modif-led form of theinvention.

Referring in detail to the drawing and particularly to Figures l and 2,the Variable ratio pulley 8 comprises a shaft i0, one end of which maybe secured to a prime mover, such as a gasoline engine, electric motor,or thelike, and a pair of tapered flanged members Il, I2, the formerbeing secured to the shaft by a key I3 and set screw I, and the latterbeing slidable along the shaft on splines l5 integral with shaft l0.

A ball bearing it is mounted on shaft I0 between the two flanged membersand in the full line position, as shown in Figure l, provides anabutment on which belt ll may rest when the belt is decl/utched from theflanged members. In this position the outer race Iii of the bearingremains stationary and the shaft and. balls rotate within it. Whenflanged member i2 moves toward member Il, the belt moves outwardly awayfrom the bearing to a clutched position and the speed of `the belt willincrease depending upon the relative position of the two anged members.The dotted line position of the belt and hanged mem- .ter l2 indicatesthe position where the beit speed is at a maximum.

The position and speed of the belt is controlled in response to thespeed of shaft l by a construction to now be described. A washer i9,slidable on shaft i8, is disposed adjacent bearing IE and abuts one endof a spring 2t, the other end of the spring abutting the hanged memberto urge it to the right in Figure 1. l"Ehe length of this spring 'andhence the force that it exerts on anged member I2, is controlled by ashaft 2| slidable axially within shaft lo, one end of this shaft havinga cross pin 22 secured thereto which projects through opposed slots 23to en'- gage the left side of washer I9, and the other end carrying asuitable grooved member 24, which may be moved to a desired pnsition byany suitable yoke and lever construction 25.

The flanged member i2 is provided with'a plurality of cylindricalchannels 26, shown slightly inclined to a radial direction, which joinat their outer ends, with. horizontal cylindrical channels 2l. Aplurality of contacting balls 428 are disposed in each of the channelsto form a ti'ain, one end of each train abutting a pin 29 aixed to adisk Sil, secured to shaft I0 against axial movement in any suitablemanner such as by collar 3l and set screw 3l'. Six evenly spaced trainsof balls and pins are shown, although it is to be understood that anynumber may be employed. At least two trains should be used and be evenlyspaced so that the pulley will remain in dynamic balance. As will beapparent, the channels form guide means for restraining the movement ofthe balls along the directions of the channels.

As previously stated, the pulley so far described has many applications;as an example, its operation will be described in a drive for a vehicle,such as an automobile. If so employed, the pulley 3 is connected to anend of the engine crankshaft and joined by a suitable heavy duty V-beltto a second pulley 32 (see Figs. 6 and '75 which preferably mayautomatically change its pitch diameter as the drive pulley changes inpitch diameter. Pulleys 'of this type are well known and no detaileddescription is deeined necessary. In one type, the poney flanges Yaremerelyspring urged toward each other and as the drive pulley changes itspitch diameter, the f flanges on the driven pulley move together orapart. The pitch diameter referred to maybe dened approximately as theVdiameter of the linner surface of the belt where it passes Vover apulley plus one thickness of the belt. In other words, the pitch circlecoincides approximately with the center line of the belt. The drivenpulley mentioned is then connected in any suite able manner with theydriving wheels of the vehicle.

The spring 2l) is so chosen tha-t when the en*- gine is idling the beltwill ride on bearing race I8, the engine then being declutched from thedriving wheels. As theA engine is sped up, as in starting the vehicle,the centrifugal force of the balls moves flange member I2 toward memberIl, thus drivingly engaging the belt, the relative pitch dia-meters ofthe pulleys 8 and 32 being as shown in Figure 6, this being analogue tolow gear in the automobile. As the vehicle gains momentum and the enginespeeds up further, the pitch diameter of pulley 3 increases and thepitch diameter of pulley 32 decreases until nnally a high ratio isobtained, as shown in Figure '7. If it be desired to adjust the par'-ticular ratio between the engine and driving wheels at a particularengine speed, this is achieved simply by manipulating lever 25 to adjustspring 29. It is apparent therefore that the speed ratio not onlychanges by infinitesimal increments of engine speed change, but also theratio at a particular engine speed may be selected.

In Figure 3 is shown another application of the invention wherein themember Ha is aiixed to a shaft ia and the balls 28 actuate, bycentrifugal force, pins 29a which are secured to pressure plate Silawhich forces plates 33 of clutch v34 together, thus driving shaft 35when the clutch plates become engaged. This construction willfindutility in electric motors, for example, where it is desired to pickup or clutch the load only after the motor has attained a pre-determinedspeed of rotation.

u In Figure 4 is shown a general application of the invention whereinthe trains of balls are utilized to actuate any control member 3017which it is desired to actuate in response to speed 'changes of shaftl0, such for example, as agovernor. Member Hb may be fixed to the shaftIb and controlled element 30h slidable thereon or vice versa.

It is to be observed that certain of the balls move into a channel 2lparallel with the axis of rotation under centrifugal force. While theseballs still produce a centrifugal force, this force has no component inthe direction parallel with the axis and therefore they loose theircontrol effect on rods 29. The balls remaining in the channels 26 stillproduce a centrifugal force which is transmitted thro-ugh the chain ofballs to control movement of rods 29. rhis construction provides amanner in which the centrifugal force and its controlling effect may belimited at certain speeds as distinguished from constructions whereinthe centrifugal force continues to increase with increase in speed; Thisis desirable because the controlling centrifugal force is required onlyup to certain limiting speeds after which further control or movement ofa member in response to centrifugal force is not desired. The equationfor centrifugal Yforce is ,M MV 2 F". R

where F is the centrifugal force, M is 'the mass of the rotating body, Rthe 'radius from the axis of rotation to its centroid and V is thelinear velocity. In the present application of this relationship, asspeed increases, the eective mass to produce a controlling eifec't onrods 2 9 Vdecreases simuitanteously with an increase of radius of itscentroid. It is apparent therefore that with increase in speed all threeof the variants are involved in the controlling force of the chain ofballs. As an illustration of the foregoing, suppose that the number oflballs be chosen so that at theV limit of movement of the controlledelevment only one ball remains in channel 26. The mass vthen becomesxed, the 'radius toits centroid fixed, and increased force becomesproportional to the square of the velocity of the single ball. This, ofcourse, limits the controlling force to the eifect produced by arelatively small mass rather than the larger mass prior to the time themass of balls movedoutwardly to leave but a single ball to produce thecontrolling effect. In the conventional centrifugaldevce, on thecontrary, 'such as `a yball governor, the balls move to a greater radiuswith increased speed but the mass desired, or at anyY other angle ofinclination.

The angle shown is convenient for production ,reasons since the holesmay readily be drilled 4from their innel` ends.

` The manner in which the holes are formed-is, of course, immaterialVand curved tubes cast in the metal or any other manner offabricatingthe channels may be em- .ployed.

f Thev pulley has been described asthe driver pulley but it will becomeapparent that it may also be employed as the driven pulley. V. I nFigure 8 a slight modification of the invenltion is shown whereinflanged member Il is formed integral with shaft lila and shaft lb fitswithin the flange Il and shaft lb. With this construction the bore forshaft lllb may be selected as desired to Vlit various size shafts.

Many modications will become apparent within the spirit of the inventionand it is not desired to limit the invention to the specic embodimentsdisclosed except as defined within the Y scope of the appended claims.

Having described the invention, claimed as new is:`

what is 1. A variable ratio pulley, comprising, a pair of axiallyaligned members having juxtaposed faces of a shape to engage the sidesof a V-belt therebetween, the width of the faces-in a radial directionbeing substantially in excess vof the thickness of the belt, meansconnecting the members together in a manner such that they rotate inunison, but are relatively movable axially, resilient means urging themembers away from each other, means rotatable with the pulley responsiveto centrifugal force for moving the members toward each other to variouspredetermined positions in accordance with the speed of rotation,whereby the effective pitch diameter of the pulley may be increased inresponse to increase in speed, the last named means including a channelin one of the axially aligned members extending outwardly from the axisof the pulley, joined at its outer end to a channel extending parallelwith the axis, and a plurality of contacting members movable within thechannels, said contacting members having a xed mass, the centrifugalforce on a portion of which becomes ineffective to produce movement ofthe members at certain speeds.

2. A variable ratio pulley in accordance with claim 1 including meansfor varying the force exerted by the resilient 'means while the pulleyis rotating, whereby the effective pitch diameter of Vthe pulley may bevaried at a predetermined speed of rotation thereof.

3. A pulley in accordance with claim 1 wherein the contacting membersare composed of spherical balls, adapted'to move in the channels in amanner such that each ball contacts an adjacent ball to form a chainthrough which force may be exerted, the end ball in the horizontalchannel applying a controlling force substantially equal to thecentrifugal force of a ball or balls disposed in the outwardly extendingchannel.

4. A centrifugal responsive controlling device,

comprising, a rotatable member, a channel extending outwardly from theaxis of rotation of the member joined at its outer end to a channelextending parallel with the axis, a mass of fixed weight movablewithinthe channels, the outer end of'the mass being adapted to applyacontrolling force, the construction being such -that only the masswithin'the outwardly extending hannel is effective to produce thecontrolling orce. Y

5. A variable ratio'pulley, comprising, a pair of axially alignedlmembers having juxtaposed frusto-conical faces for receiving a V-belttherebetween, the width of the faces in a radial direction beingsubstantially in excess of the thickness of the belt, an idler pulleydisposed axially between the members upon which the belt may rest indisconnected relation to the members when the pulley rotates below Vapredetermined speed, means connecting the members together in a mannersuch that they rotate in unison but are relatively movable axially,suicient range of movement being provided so that one of the membersfmaytelescope over the idler pulley, resilient means urging the members awayfrom each other, means rotatable with the pulley responsive tocentrifugal force for moving the members toward each other to variouspredetermined positions, Ydepending upon the speed of rotation, wherebythe eiective pitch diameter of the pulley may be appreciably increasedin response to increase in pulley speed, the last named means includinga cylindrical channel in one of the axially aligned members extendingoutwardly from the axis of the pulley, joined at its outer end to achannel extending parallel with Athe axis, and a chain of contactingspherical l 'balls disposed to move in the channels, the end ball in thehorizontal channel applying a controlling force substantially equal tothe centrifugal force of a ball or balls disposed in the outwardlyextending channel.

6. A pulley in accordance with claim 5 wherein at least two sets ofchannels and chains of balls are provided in the pulley, arranged in amanner such that the pulley remains in dynamic balance.

7. A pulley in accordance with claim 6 wherein pins are providedextending into the outer ends of the horizontal channels, one end ofeach pin engaging an end ball in a chain, the other end of the pin beingfixed against axial movement relative to one of said axially alignedmembers.

8. A variable ratio pulley, comprising, a shaft, one end of which isadapted to be connected to a rotatable member, a frusto-conical iiangedniember secured to the shaft, a ball bearing on the shaft adjacent theflanged member, a second frusto-conical member facing the first memberin a manner to provide a V pulley, the second member being rotatablewith the shaft and slidable thereon, a recess `being provided thereinwhereby it may telescope over the ball bearing, a spring interposedbetween the ball bearing and second member for urging the latter awayfrom the first member, an outwardly extending channel in the secondmember joined at its end by a horizontal channel, a chain of ballsdisposed in the channels, a pinextending into the outer end of thehorizontal channel, and means for securing the pin to the shaft in fixedrelation to the rst flanged member.

9. A pulley in accordance with claim 8 wherein an abutment is providedadjacent one end of the spring, the position of which is controlled byassegni 7 n'ieanswiihinihe shaft extending beyond' one eiidtheff. v Y

'1101 A cemrugai responsive controlling de-- vice, comprising, arotatable member having 'tW'gle means being Sli'h'that the controlling.f'r'ce is substantially equal to the centrifugal force exerted by onlythat portion of the mass ldisposed along the rst named guide meansWhenthe member is rotating with prtioh'sv f thema'ss disposed along bothguide means.

11'. A variable ratio pulley,'ciprisiiig, a pair of axially alignedmembers having juxtaposed faces of a shape'to engage the sides" of aV-belt therebetween, the Width of 'the faces in a radial direction beingsubstantially in ex'cess of the `thickness of the belt, means connectingthe members Ytogether in a manner such' that they imayrotate in Vunisonand'move relatively axially, fandnieans 'rotatable with the 'pulley foreffecting-the `axial movement, including; guide'me'ans extending`outwardly from the axis of the pulley .joined *at the -outer lenelVthereof Vto guide means .extendingsubstantially parallel with ytheaxis, and a plurality of-contacting members having a nxed `mass movablealong the 4guide means.

12. A variable ratio pulley, comprising; -a pair ,oi axially alignedmembers having juxtaposed ,8 Vfaciles-"offa shapetoenwgage the sidesfofaV'-be1t therebetween; the Widthy vof the faces in a vradial directionbeing substantially in excess of the thickness of the belt, mea-nsconnecting the members together in a `manner such that they rotate' inunison, but are relatively movable axially, resilient means urging theV`members away'fro'm each other, means rotatable Withthe pulleyiresponsiveto centrifugal force for moving the4V members toward eachother tovarious pre= .determined positions in accordance with the Speed ofrotation, Whereby'the effective pitch diameter of the4 pulley l may beincreased in response to increase in speed, the last named meansincluding guide means extending o ut- Wa'r'd'lly@fromV the axis `of thepulley, joined atthe outer' endthereof the guide means extendingsubstantially ,parallel with the axis, and a plurality of contactinglmembers having a -xed Vmass movable along the guide means.

CHARLES H. MIN-ER.

REFERENCES ACITED y The following references are of record in `the -lerof this patent:V

UNlTED STATES PATENTS .FOREIGN PATENTS Country Date 4GreatBritain July22, 1996 ANurrrber Number

